Jet fuel composition



United States Patent Ofitice 3,346,355 JET FUEL COMPOSITION George W. Eckert, Wappingers Falls, N.Y., assignor to Texaco Inc., New York, N.Y., a corporation of Delaware No Drawing. Filed July 10, 1964, Ser. No. 381,917

- 3 Claims. (Cl..44-66) ABSTRACT OF THE DISCLOSURE This invention relates to a novel jet fuel composition exhibiting the unique property of reducing wear in a jet engine. The-jet fuel of the invention is also outstanding in the ease in which emulsions are removed as determined by the water separometer test. These important properties are obtainedby incorporating in the fuel composition a combination of additives comprising a fatty material consisting essentially of a compound selected from the group consisting of dimers and trimers of ethylenic fatty acids and mixtures thereof and a phenoliccompound.

Either in aircraft usageorin stationary power installations, jet engines require the delivery of large volumes of fuel under pressure to the combustion zone of the engine. The large fuel demands of the engine places a critical burden on the fuel pump which has the function of delivering the required fuel under the proper conditions. Now, jet fuel compositions, .being light hydrocarbons, have little lubricity or lubricating value in themselves with the result that the fuel pump is operated under high weaninducing conditions. These severe operating conditions have caused serious breakdowns in the fuel delivery system due to excessive wear of the fuelpump mechanism. Anti-wear im provement in jet engines has, heretofore, been achieved through the lubricating oil used and it is novel to obtain such an improvement through an additive-containing jet fuel composition.

Another critical problem encountered in the operation of jet engines and particularly in connection with the operation of jet engine aircraft is that caused by water in the fuel, the presence of a minor amount of which is inevitable. Water has a tendency to form emulsions with any additives present in the fuel and it is frequently the case that these emulsions are not readily filterable from the fuel and are passed into the engine. These emulsions can cause a blockage in the fuel feed system and actually stop operation of the engine. The additive combination employed in the jet fuel of this invention is outstanding in that emulsions formed with the water contained in the fuel are readily separated as shown by the water separometer test.

The jet fuel of the invention comprises normally liquid hydrocarbons, that is light napthas and kerosenes boiling in the range of 90 to 500 F., and containing the additive combination comprising a fatty material consisting essentially of a compound selected from the group consisting 3,346,355 Patented Oct. 10, 1967 of dimers and trimers of ethylenic fatty acids and mixtures thereof, said fatty acids having from 12 to 22 carbon atoms and a phenolic compound represented by the formula:

in which R and R each represent hydrogen or a lower alkyl-radical having from 1 to 6 carbon atoms. More specifically, the jet fuel of the invention will contain from about 0.001 to 0.5 percent by weight of said fatty material and about 0.001 to about 1.0 weight percent of said phenolic compound.

The fatty materials of this invention are commonly referred to as dimers and trirners and actually are polymers of linoleic acid. These acids are produced by polymerizing linoleic acid under conditions to yield ap proximately of the dimer, approximately 12% of the trimer and only a few, for example, 3% of unpolymerized monomer. The preferred polymerized linoleic acid component of the present composition is one sold under the trade designation Empol 1022 having the following significant properties:

Solubility, insoluble in water, soluble in oils, waxes, fuels.

The polymerized linoleic acid component of the jetfuel of this invention is generally employed in a range from about 0.001 to about 0.50 percent of the jet fuel composition. A preferred concentration of the polymerized linoleic acid is an amount from about 0.001 to about 0.05 percent. A significant aspect of the polymerized linoleic acid component of the fuel is that it has an adverse effect on the Water separometer Index of the fuel composition when it is used alone or in the absence of the phenolic component.-

The phenolic compound of the jet fuel composition of the invention is represented by the formula:

in which R and R each represent hydrogen or a lower aliphatic radical having from 1 to about 6 carbon atoms. Phenol is the preferred additive in this class for reasons of availability and cost. The lower molecular weight mon-oand dialkyl substituted phenols including monoand dimethyl and monoand diethylphenols and the like are also effective for imparting the improved properties of the jet fuel composition of the invention. The phenolic component of the jet fuel is employed in a concentration from about 0.001 to about 1 percent, with the preferred amount being in the range from about 0.005 to about 0.1 percent.

The base fuel from which the jet fuel of the invention is prepared consists essentially of hydrocarbons boiling in the range from about 90 to 500 F. Typical jet fuels which can be improved according to this invention include JP-S a mixture of about 70 percent gasoline and 30 percent light distillate having a 90 percent evaporated point of 470 F., JP-4, a mixture of about 65 percent gasoline and 35 percent light distillate and JP-5, an especially fractionated kerosene having a high flash point and a low freezing point.

The following examples illustrate the practice of this invention. The base jet fuel employed in these examples consisted of a 90 percent parafiinic percent aromatic hydrocarbon mixture boiling in the range of 202 to 272 F.

The Four Ball Wear Test was employed to determine the improved anti-wear properties of the jet fuel composition of the invention. The test machine employed in this test comprises a system of four steel balls, three of which are in contact with each other in one plane in a fixed triangular position in a reservoir containing the sample and a fourth ball above and in contact with the other three. In carrying out the test, the upper ball is rotated while it is pressed against the lower three at any desired pressure by means of a suitable weight applied to a lever arm. The diameters of the scars on the three lower balls are measured by means of a low power microscope. The average diameter measured in two directions on each of the three lower balls is taken as a measure of the antiwear characteristics of the fuel. Results of this test are given in Table I below:

TABLE I WEAR TEST This test shows the remarkable improvement in the anti-wear properties of the fuel composition brought about by the additive combination.

The Water Separometer Index value of the fuel of the invention was determined according to Federal Test Method 791a-3256 entitled, Determination of Water Separation Properties of Aviation Turbine Fuels. According to this test, 2,000 cc. of fuel plus 2 cc. of water are circulated in a closed system by means of a small gear pump having an output rating of 400 cc. per minute. The microammeter in the apparatus is set before water addition so that the Water Separometer Index value of the base fuel without water is 100. Fuel and water are circulated for five minutes to insure complete mixing of the water-fuel mixture. A portion of this fuel mixture is then circulated through a glass system at a rate of 150 cc./ min. This effluent passes through a glass fiber filter coalescer and then through a glass tube equipped with a light and photoelectric cell for determining the light transmission upon which the Water Separometer Index is based. The Water Separometer Index value of the circulated fuel-water mixture is taken in the photoelectric measuring device after the mixture has been passed through the glass filter. The higher the Water Separometer Index the better the fuel is with respect to its water separation properties.

The base jet fuel described above after water addition had a Water Separometer Index value of 86. The same fuel containing both water and the additive combination of 18 ptb. of dimer acids and 18 ptb. of phenol had a Water Separometer Index value of 95. This is a substantial improvement in the water separation property of the fuel which can be of critical importance in the operation of a jet engine.

The novel jet fuel compositions of the invention has been shown to possess unusual anti-wear properties and excellent Water Separometer Index values. This improved fuel provides substantial advantages in maintaining extended operation and reliability of jet engines.

Obviously, many modifications and variations of the invention, as hereinabove set forth, may be made without departing from the spirit and scope thereof, and therefore, only such limitations should be made as are indicated in the appended claims.

I claim:

1. A jet fuel composition comprising hydrocarbons boiling in the range from about to 500 F. containing from about 0.001 to 0.50 percent of a fatty material consisting essentially of a compound selected from the group consisting of dimers and trimers of linoleic acid and mixtures thereof and from about 0.001 to 1.0 percent by weight of phenol.

2. A jet fuel composition according to claim 1 in which said fatty material is polymerized linoleic acid consistng essentally of the dimer.

3. A jet fuel according to claim 1 in which said fatty material is employed in the range from about 0.001 to 0.05 percent and said phenolic compound is employed in the range from about 0.005 to 0.1 percent.

References Cited UNITED STATES PATENTS 3,019,097 1/ 1962 Ecke et al. 44-78 3,180,832 4/1965 Furey 2525'6 3,251,663 5/1966 Andress, et al. 44-66 3,273,981 9/1966 Furey 252-56 X DANIEL E. WYMAN, Primary Examiner.

W. J. SHINE, Assistant Examiner. 

1. A JET FUEL COMPOSITION COMPRISING HYDROCARBONS BOILING IN THE RANGE FROM ABOUT 90 TO 500*F. CONTAINING FROM ABOUT 0.001 TO 0.50 PERCENT OF A FATTY MATERIAL CONSISTING ESSENTIALLY OF A COMPOUND SELECTED FROM THE GROUP CONSISTING OF DIMERS AND TRIMERS OF LINOLEIC ACID AND MIXTURES THEREOF AND FROM ABOUT 0.001 TO 1.0 PERCENT BY WEIGHT OF PHENOL. 